The 3rd General Partnership Project (3GPP), which is a standardization project, has standardized the Evolved Universal Terrestrial Radio Access (EUTRA), in which high-speed communication is realized by adopting an Orthogonal Frequency Division Multiplexing (OFDM) communication scheme and flexible scheduling in a unit of prescribed frequency and time called a resource block. The overall communications that have employed the standardized EUTRA technology may be referred to as “Long Term Evolution (LTE) communications”.
Moreover, the 3GPP discusses the Advanced EUTRA (A-EUTRA), which realizes higher-speed data transmission and has upper compatibility with the EUTRA. The EUTRA relates to a communication system based on a network in which base station devices have substantially the identical cell configuration (cell size); however, regarding the A-EUTRA, discussion is made on a communication system based on a network (heterogeneous wireless network, heterogeneous network) in which base station devices (cells) having different configurations coexist in the same area.
The 3GPP discusses Licensed Assisted Access (LAA) communications that enable communication in an unlicensed frequency (unlicensed band) using a licensed frequency (licensed band) specified in the LTE (NPL 1).
NPL 1 discusses a method for measuring a Received Signal Strength Indicator (RSSI) relating to interference and noise to perform effective communication.